[PATCH AUTOSEL 4.9 14/50] net: vmxnet3: fix possible buffer overflow caused by bad DMA value in vmxnet3_get_rss()

[Sasha Levin]

From: Jia-Ju Bai <baijiaju1...@gmail.com>

[ Upstream commit 3e1c6846b9e108740ef8a37be80314053f5dd52a ]

The value adapter->rss_conf is stored in DMA memory, and it is assigned
to rssConf, so rssConf->indTableSize can be modified at anytime by
malicious hardware. Because rssConf->indTableSize is assigned to n,
buffer overflow may occur when the code "rssConf->indTable[n]" is
executed.

To fix this possible bug, n is checked after being used.

Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/net/vmxnet3/vmxnet3_ethtool.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/vmxnet3/vmxnet3_ethtool.c 
b/drivers/net/vmxnet3/vmxnet3_ethtool.c
index aabc6ef366b4..d63b83605748 100644
--- a/drivers/net/vmxnet3/vmxnet3_ethtool.c
+++ b/drivers/net/vmxnet3/vmxnet3_ethtool.c
@@ -691,6 +691,8 @@ vmxnet3_get_rss(struct net_device *netdev, u32 *p, u8 *key, 
u8 *hfunc)
                *hfunc = ETH_RSS_HASH_TOP;
        if (!p)
                return 0;
+       if (n > UPT1_RSS_MAX_IND_TABLE_SIZE)
+               return 0;
        while (n--)
                p[n] = rssConf->indTable[n];
        return 0;
-- 
2.25.1